b698cc1338
Added detailed information about the SX126x and its current state in development. Added directories for wireless character driver and LPWAN. Added indexes to each directory and its contents within. Signed-off-by: Kevin Witteveen (MartiniMarter) <kevinwit1999@gmail.com>
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2.6 KiB
ReStructuredText
80 lines
2.6 KiB
ReStructuredText
.. _chardev:
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========================
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Character Device Drivers
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========================
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Character device drivers have these properties:
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- ``include/nuttx/fs/fs.h``. All structures and APIs needed
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to work with character drivers are provided in this header
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file.
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- ``struct file_operations``. Each character device driver
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must implement an instance of ``struct file_operations``. That
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structure defines a call table with the following methods:
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- ``int register_driver(const char *path, const struct file_operations *fops, mode_t mode, void *priv);``.
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Each character driver registers itself by calling
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``register_driver()``, passing it the ``path`` where it will
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appear in the :ref:`pseudo file system <file_system_overview>` and it's
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initialized instance of ``struct file_operations``.
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- **User Access**. After it has been registered, the character
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driver can be accessed by user code using the standard driver
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operations including
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``open()``, ``close()``, ``read()``, ``write()``, etc.
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- **Specialized Character Drivers**. Within the common character
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driver framework, there are different specific varieties of
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*specialized* character drivers. The unique requirements of the
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underlying device hardware often mandates some customization of
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the character driver. These customizations tend to take the
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form of:
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- Device-specific ``ioctl()`` commands used to performed
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specialized operations on the device. These ``ioctl()`` will
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be documented in header files under ``include/nuttx`` that
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detail the specific device interface.
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- Specialized I/O formats. Some devices will require that
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``read()`` and/or ``write()`` operations use data conforming
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to a specific format, rather than a plain stream of bytes.
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These specialized I/O formats will be documented in header
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files under ``include/nuttx`` that detail the specific
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device interface. The typical representation of the I/O
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format will be a C structure definition.
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The specialized character drivers support by NuttX are
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documented in the following paragraphs.
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- **Examples**: ``drivers/dev_null.c``, ``drivers/fifo.c``,
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``drivers/serial.c``, etc.
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.. toctree::
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:caption: Supported Drivers
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:maxdepth: 2
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1wire.rst
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analog/index.rst
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bch.rst
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can.rst
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contactless.rst
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crypto/index.rst
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efuse.rst
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i2s.rst
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input/index.rst
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ipcc.rst
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leds/index.rst
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loop.rst
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math.rst
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modem.rst
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motor/index.rst
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note.rst
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nullzero.rst
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quadrature.rst
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rc.rst
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rf.rst
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serial.rst
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timers/index.rst
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touchscreen.rst
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wireless/index.rst
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